A video recording of a Minneapolis police officer killing George Floyd by kneeling on his neck set off this summer’s record-breaking protests against police violence and racist policing. But as Jamila Michener outlined here at TMC in June, Floyd’s killing was just the spark to ignite outrage against broader systemic racial injustice.

For example, U.S. law enforcement disproportionately police people who are Black, Latino and/or poor. Individuals identifying with these groups bear the long-term negative consequences of constant surveillance. What’s more, they are a regular source of revenue for cash-strapped governments, especially in fees and fines from traffic violations.

Our research questions how discriminatory policing interacts with increasing government needs and demands for revenue. To better understand this relationship, we examined traffic stops in Missouri. Overall, Black drivers are disproportionately stopped and cited in the state. But when local governments experience budget shortfalls, which increase pressure to generate revenue, officers increasingly ticket White drivers.

Here's what we already know about racial disparities in traffic stops

State and local governments rely so much on traffic revenue that even the pandemic-related drop in driving did not reduce Missouri state troopers’ ticketing for traffic violations. Many U.S. residents know that traffic tickets help prop up state and local budgets. Drivers have been warned of — or caught by — “speed traps,” cited for violating state vehicle codes for broken taillights or stopped for temporarily shifting a few inches over a lane divider.

Both news media and scholars have investigated this use of fees and fines. Sociologist Alexes Harris and law professor Jeffrey Fagan and economist Elliott Ash compared traffic stop revenue to a form of latent taxation.

The Department of Justice’s 2015 investigation of Ferguson, Mo., found that the city’s law enforcement focused on ticketing rather than public safety and that police tended to see residents of the city’s predominantly Black neighborhoods as sources of revenue. In an April 2014 memo, the mayor of nearby Edmundson, Mo., reminded police sergeants that traffic stop revenue is what funds officers’ salary increases. This type of pressure is important, because scholars have shown that officers increase their ticketing activity when local governments experience budgetary shortfalls.

Racial disparities in traffic stops have also been well-documented in political science, economics, sociology and criminology, the media, and litigation, including the 2015 Ferguson report, which showed that everyday policing practices, including traffic and pedestrian stops, were a form of social, emotional and fiscal taxation disproportionately levied on Black and Latino civilians.

We looked into how those two systems interact

We wanted to know more about how the pressure on police to bring in revenue from ticketing interacts with systems of racial inequality. Our research paper documenting that work was recently published in the Journal of Race, Ethnicity and Politics.

Focusing on Missouri, we paired data from 2001 to 2012 about the racial breakdown in traffic tickets, which we got from the state attorney general’s office, with data from those same years on Missouri municipal budgets, which we got from the IndFin local government finances data set.

In Missouri, as in much of the rest of the United States, Black and Latino drivers are stopped, searched, cited and arrested at higher rates than White drivers. To analyze how local budgetary shortfalls might influence these patterns, we defined budget shortfalls as years in which a local government’s revenue had dropped compared with the previous year. We then measured changes in policing activity, focusing on traffic citations, searches and arrests, in the year after the municipality experienced the budget shortfall.

When budgets fall short, officers increase revenue by stopping more White drivers

When a Missouri municipality faces a budget shortfall, its policing agencies start issuing more traffic tickets — but only to White drivers. That means that in areas with a revenue shortfall, White drivers are stopped and ticketed more often.

Why? While we cannot definitively answer this, we conducted some analyses to investigate what could be driving these shifts. We found that the increases in citations of White drivers are concentrated in areas where White residents generally have higher incomes than Black residents. Our supposition is that ticketing increases in those areas are likely to produce the highest revenue stream. What’s more, we also find that citations of White drivers increase in areas where Black drivers are already overpoliced. Officers may increase their policing of White drivers when it would be difficult to find more Black drivers to stop.

Our findings confirm existing knowledge: Police disproportionately target Black and Latino drivers, and when municipalities run short of funds, officers increase their traffic enforcement to bring in more revenue through fees and fines.

However, our findings, surprisingly, show that budget pressures shift officers’ racial targeting in an unexpected direction: toward White drivers. This might be because of two existing and persistent inequalities: First, that White drivers tend to have higher incomes than non-White drivers, and second, that Black drivers are already overpoliced.

In other words, more equitable traffic enforcement remains the exception rather than the rule.

Allison P. Harris (@AlliPatter) is an assistant professor of political science at Yale University.

Elliott Ash (@ellliottt) is an assistant professor of law, economics, and data science at ETH Zurich.

Jeffrey A. Fagan (@JFagan46) is the Isidor and Seville Sulzbacher Professor of Law at Columbia University Law School.